1. Field of the Invention
The present invention relates to a liquid jet recording apparatus and especially to a liquid jet recording apparatus improved in recording speed.
2. Related Background Art
The liquid jet recording (ink-jet recording) system which makes a record by forming droplets of a recording liquid such as an ink and emitting the droplets on to a recording material such as paper has attracted public attention because according to this recording system, recording noise is very low and can be ignored, high-speed recording is possible and recording can be made on a plain paper without special treatment such as fixation. Thus, various types of the recording systems have recently been intensively studied.
The recording head part of recording apparatus used for ink-jet recording generally comprises orifices for discharging ink (liquid discharge port), an ink passage (liquid passage) having a portion where engergy for discharging the ink acts on the ink and an ink chamber for storage of ink to be supplied to said ink passage.
Furthermore, the recording head part of recording apparatus used for ink-jet recording generally has a plurality of orifices and orifices which discharge ink of the same color are supplied with the ink from a common ink chamber in the recording head. To this ink chamber, an ink is supplied from an ink tank through an ink supply pipe.
Operation frequency of the ink-jet recording head depends on the time required for meniscus of ink in the orifices which moves back to the inside of the ink passage after discharging of liquid droplets being restored to the original state by the surface tension of the ink. When liquid droplets are simultaneously discharged from a plurality of orifices of the ink-jet recording head as referred to above, restoration amount of the ink meniscus after discharging of liquid droplets varies depending on the number of the simultaneously discharged liquid droplets and so the time required for restoration of the ink meniscus varies and thus operation frequency also varies. Specifically, this operation frequency decreases with increase of the number of the simultaneously discharged liquid droplets.
Therefore, in the conventional ink-jet recording apparatuses provided with such an ink-jet recording head, when maximum frequency of driving pulse applied to recording head is set so as to attain high-speed recording, this must be set in correspondence with the lowest operation frequency of recording head, namely, the response frequency when the number of the simultaneously discharged liquid droplets is a maximum. Therefore, there has been a limitation in improvement of recording speed.